The use of electronic bladder diaries (BD) may have advantages such as intuitive data entry or reducing calculation time.  
As the use of smart-phones is spread world-wide, we designed an easy to use electronic BD (eDM3d) as a mobile app based on the already Spanish validated 3-day BD (DM3d), which includes a frequency-volume chart, urgency episodes, urgency intensity (PPIUS scale), incontinence episodes and fluid intake (1). Interface obtained consisted in only 4 buttons (micturition, intake, wake-up, sleep) that had to be clicked to create an event.  
Our aim was to validate the eDM3d through its comparison with the paper DM3d.

Epidemiological and cross-sectional prospective study. Patients older than 18, with overactive bladder syndrome (OABs) or nocturia and who had a smart-phone were included. 
They filled in the International Consultation on Incontinence -Short Form (ICIQ), the Bladder Control Self-Assessment Questionnaire (BSAQ), the paper DM3d and the eDM3d (test) during the first week. After 15 days they completed the eDM3d again (retest). Finally, they answered a direct question about satisfaction: "If you had to complete a BD again, would you choose the paper or the app version?". 
Forty two variables were obtained from each BD and their mean values were calculated for comparison. We assessed the feasibility of the eDM3d (% of completion), reliability (comparison test-retest; Mc Nemar test for qualitative variables, intraclass correlation coficient -ICC- for quantitative variables), paper DM3d and electronic eDM3d correlation (Kappa index for qualitative variables and ICC for quantitative variables) and convergent validity (eDM3d vs questionnaires; Spearman correlation). Calculated sample size with a confidence level of 95% for an ICC 0.8-0.9 was 136. Ethical approval was obtained from the Ethical Board and all patients signed an informed consent before entering the study.

Fifty four (39.7%) women and 82 (60.3%) men were included, with mean age (SD) of 59.6 ± 12.2 years. One hundred thirteen (83.1%) patients had OABs and 125 (91.9%) patients complained of nocturia. 

- Feasibility: 91.2% patients completed ≥80% variables of the eDM3d.

- Test- retest reliability: No significant differences were obtained at McNemar test (p0.063-p0.388). The ICC ranged from 0.85 to 0.97 for all variables (p<0.05)

- Paper - app correlation:  Kappa index ranged from 0.74 to 0.88 (p<0.05).  The ICC ranged from 0.87 to 0.94 (p<0.05).

- Convergent validity: Spearman correlation coefficients for ICIQ and BSAQ ranged from 0.23 to 0.61 (p<0.05). 

One hundred twenty-two (89.7%) patients would choose the eDM3d, 5 (3.6%) the paper version and 9 (6.6%) either indistinctly.

Our study suggests that the new eDM3d presents good feasibility and an excellent patients’ acceptance. Regarding reliability and paper-app correlation, results of kappa index test and ICC were good to excellent and results of Spearmen correlation indicate a good convergent validity. 
The main limitation of the study is that only patients who possessed a smart-phone could be included in the study. Thus, the electronic bladder diary as an app, eDM3d, could be used in the clinical practice in the assessment of patients with overactive bladder syndrome or nocturia and who have a smart-phone.

The eDM3d showed good feasibility, reliability and validity to be used in the assessment of patients with overactive bladder syndrome or nocturia, with high patients' satisfaction rate.

Jimenez Cidre MA. The 3-day bladder diary is a feasible, reliable and valid tool to evaluate the lower urinary tract symptoms in women. Neurourol Urodyn. 2015;34(2):128-32